ANSI Common Lisp 3 Evaluation and Compilation 3.5 Error Checking in Function Calls 3.5.1 Argument Mismatch Detection
188.8.131.52 Too Many Arguments
It is not permitted to supply too many arguments to a function.
Too many arguments means more arguments than the number of required parameters
plus the number of optional parameters; however, if the function
uses &rest or &key, it is not possible for it to receive too many arguments.
If this situation occurs in a safe call,
an error of type program-error must be signaled;
and in an unsafe call the situation has undefined consequences.